EXCHANGE 


•f  20 

* 


The  Osmotic  Pressure  of 
Cane  Sugar  Solu- 
tions at  5°. 


DISSERTATION. 


SUBMITTED  TO  THE  BOARD  OF   UNIVERSITY   STUDIES  OF 

THE   JOHNS   HOPKINS    UNIVERSITY    FOR   THE 

DEGREE  OF  DOCTOR  OF  PHILOSOPHY. 


BY 


EUGENE  EDWARD  GILL. 


1909 


CHICAGO,  ILL. 

1910 


The  Osmotic  Pressure  of 
Cane  Sugar  Solu- 
tions at  5°. 


DISSERTATION. 


SUBMITTED  TO  THE  BOARD   OF   UNIVERSITY   STUDIES  OF 

THE   JOHNS   HOPKINS    UNIVERSITY    FOR    THE 

DEGREE  OF  DOCTOR  OF  PHILOSOPHY. 


BY 


EUGENE  EDWARD  GILL, 


1909 


CHICAGO,  ILL. 
1910 


McElroy  Publishing  Company 
6219  Cottage  Grove  Ave. 
Chicago    . 


CONTENTS. 


Page 

Acknowledgment    4 

Introduction    5 

Improvement  in  Cells 5 

Treatment  of  Membranes 6 

Temperature  Regulations   6 

Improvement    in    Manometers    8 

Discussion  of  Previous  Series   8 

Purification  of  Sugar   9 

Explanation  of  Tables   9 

Comment  on  Tables   18 

Comparison  of  Results    18 

Conclusion 19 

Biography    20 


239401 


ACKNOWLEDGMENT. 


The  author  wishes  to  express  his  sincere  gratitude  to  President 
Remsen,  Professor  Morse,  Professor  Jones,  Associate  Professor  Acree 
for  instruction  in  the  lecture  room  and  laboratory,  and  to  Dr. 
Schwartz  for  instruction  in  his  second  subordinate  subject.  Especial 
thanks  are  due  to  Professor  Morse,  under  whose  guidance  this  inves- 
tigation was  pursued.  The  author  is  indebted  also  to  Dr.  W.  W. 
Holland  for  assistance  in  connection  with  the  work. 


THE   OSMOTIC   PRESSURE   OF   CANE   SUGAR   SOLUTIONS 

AT  5°. 


In  connection  with  the  determination  of  the  temperature  co-effi- 
cient of  the  osmotic  pressure  of  cane  sugar  solutions,  which  work  is 
being  carried  out  in  this  laboratory,  it  seemed  advisable  to  repeat  the 
series  of  measurements  at  5°.  In  1907,  Dr.  P.  B.  Dunbar  made  a 
series  of  measurements  of  the  osmotic  pressure  of  cane  sugar  solu- 
tions at  approximately  this  temperature. 

Since  then,  however,  many  improvements  have  been  made  in 
the  method,  so  that  the  degree  of  accuracy  of  the  work  has  been  very 
much  increased.  Further,  it  seemed  necessary  to  have  a  series  of 
measurements  at  5°,  which  had  been  taken  under  the  same  conditions 
as  the  series  at  other  temperatures  with  which  it  is  desired  to  make 
comparison;  namely,  at  0°,  10°,  15°,  20°,  25°,  and  30°.  The  im- 
provements in  the  method  may  be  discussed  briefly  under  three  gen- 
eral heads:  First,  cells;  second,  temperature  regulation;  third,  mano- 
meters. 

In  this  series  all  the  measurements  have  been  taken  with  the 
new  style  cell,  which  was  designed  last  year.  The  construction  of 
this  cell  is  such  that  the  time  of  setting  up  and  taking  down  of  the 
cell  after  a  measurement  is  very  materially  reduced.  With  the  old 
style  cell,  with  which  the  earlier  measurements  at  5°  were  taken, 
much  time  was  consumed  in  setting  up  the  cell,  the  cell  being  held 
in  the  warm  hand  all  the  time,  so  that  temperature  effects  were  pro- 
duced and  dilution  occurring,  since  the  water  on  the  outside  of  the 
cell  always  dilutes  the  solution  on  the  inside  unless  the  maximum 
osmotic  pressure  is  developed. 

Again,  when  the  cell  was  taken  down,  aside  from  the  time  con- 
sumed in  the  operation,  there  was  the  disadvantage  of  diminished 
pressure  on  the  cell  contents  when  the  manometer  was  withdrawn. 
This  caused  further  dilution.  Under  these  conditions  it  was  impos- 
sible to  tell  whether  the  change  in  rotation  observed  at  the  end  of  the 
experiment  was  due  entirely  to  these,  or  in  part  to  other,  causes  of 
dilution,  or  to  the  inversion  of  the  cane  sugar  during  the  progress  of 
the  measurement. 

With  the  use  of  the  new  style  cell  and  the  improved  arrangement 
for  closing  the  cell,  which  has  been  described  in  an  article  by  Morse 
and  Mears  in  The  American  Chemical  Journal  for  September,  1908, 
no  change  in  rotation  has  been  found  in  any  case  where  the  cell  has 
developed  its  maximum  osmotic  pressure.  All  former  losses  in  rota- 
tion were  then  certainly  due  mainly  to  dilution  of  the  cell  contents 
during  the  manipulation  of  the  cell  and  its  manometer  prior  to  and 
subsequent  to  the  measurement. 

The  hypodermic  needle  and  its  use  as  described  in  the  article 
above  referred  to  has  been  modified  somewhat,  but  not  changed  in  its 
essential  features.  The  head  of  the  needle  has  been  replaced  by  a 
threaded  brass  cap  upon  which  is  placed  a  stout  leather  washer.  A 
steel  plug,  threaded  to  fit  the  brass  cap  on  the  needle  is  used  to  close 
the  opening  after  the  manometer  has  been  forced  into  the  cell  the 
desired  amount.  The  advantage  of  this  method  of  closing  the  cell 
is  that  it  can  be  closed  at  atmospheric  pressure,  and  in  less  than  a 
minute's  time.  In  taking  down  the  cell,  it  is  only  necessary  to  re- 
move this  steel  plug  and  atmospheric  pressure  on  the  cell  contents 
results  at  once.  The  cell  can  be  taken  down  without  subjecting  the 
contents  to  the  least  diminished  pressure. 


In  the  treatment  of  the  membranes,  some  observations  have  been 
made  during  the  year's  work  that  should  be  mentioned.  It  is  essen- 
tial that  the  membranes  be  soaked  for  sometime  in  thymol  water 
between  successive  measurements.  The  necessity  of  this  soaking 
has  been  impressed  on  us  by  the  improved  behavior  of  the  mem- 
branes after  a  vacation.  Membranes  which  had  been  soaking  with 
frequent  changes  of  water  during  the  summer  months  behaved  ex- 
ceptionally well  in  the  fall.  Successive  measurements  could  be  taken 
with  them  with  only  a  day  or  two  between.  As  the  work  went  on, 
however,  it  became  evident  that  these  membranes  were  requiring 
more  and  more  rest  between  measurements.  The  same  observation 
was  made  with  a  new  lot  of  membranes  that  were  developed  during 
the  fall  months.  An  occasional  measurement  was  secured  from  some 
of  these  membranes  before  the  Christmas  holidays,  but  they  were  by 
no  means  reliable  membranes  up  to  that  time.  It  so  happend  that 
they  had  two  weeks'  rest  with  the  usual  soaking  in  thymol  water, 
and  when  we  came  to  take  measurements  with  them  in  January  they 
turned  out  to  be  the  most  reliable  membranes  we  had.  This  will  be 
evident,  upon  an  examination  of  the  tables  showing  the  measure- 
ments, by  the  frequent  occurrence  of  cells  J  and  K  in  the  work. 

We  are  not  able  to  come  to  any  conclusion  as  to  why  the  soak- 
ing and  resting  of  the  membranes  is  beneficial.  The  good  condition 
of  the  membrane  can  only  be  judged  by  the  results  it  produces,  since, 
from  the  nature  of  the  case,  it  can  be  examined  in  no  other  way. 
It  seems  unlikely  that  the  good  results  are  due  altogether  to  a  re- 
moval from  the  membrane  by  the  water  of  substances  foreign  to  it. 
If  the  benefit  should  be  due  to  the  rest,  one  has  plenty  of  analogies 
in  the  mechanical  world.  It  is  well  known  that  to  obtain  the  great- 
est efficiency  from  machinery  run  under  a  high  strain  frequent  rest 
is  necessary.  The  membranes  which  we  use  are  certainly  very  deli- 
cately constructed  and  are  subjected  to  comparatively  large  pres- 
sures, in  the  case  of  normal  solutions  about  twenty-six  atmospheres 
being  developed. 

Since  the  first  series  of  measurements  were  made  at  5°  many 
changes  have  been  made  in  the  baths  in  which  the  cells  are  placed 
while  the  experiment  is  in  progress,  with  a  view  to  preventing  en- 
tirely what  are  known  as  "thermometer  effects." 

The  temperature  of  the  water  in  this  bath  is  regulated  by  a  cir- 
culating system  which  may  be  briefly  described.  Supported  on  an 
open  frame  work  near  the  bottom  of  the  bath  is  a  series  of  connected 
horizontal  brass  pipes  with  an  aggregate  length  of  10  meters.  The 
hydrant  water  enters  this  system  at  the  lowest  point  and  passes 
through  a  succession  of  pipes,  always  in  a  horizontal  or  upward 
direction  (to  prevent  the  collection  of  air),  thence  through  a  ver- 
tical pipe  to  the  air  space  above.  The  vertical  pipe  here 
connects  with  a  second  system  of  horizontal  pipes,  placed  one 
above  another,  which  is  fixed  to  the  walls  of  the  air  space; 
and  the  water,  after  circulating  through  this,  enters  a  third  system  of 
horizontal  pipes  which  is  suspended  from  the  top  of  the  bath.  If 
necessary  the  hydrant  water  is  cooled,  by  passing  it  through  a  block 
tin  coil  surrounded  by  ice,  before  it  enters  the  bath.  The  slowly  cir- 
culating water,  while  passing  through  the  pipes  lying  in  the  bottom 
of  the  bath,  is  warmed  nearly  to  the  temperature  of  the  bath  water, 
and  it  may  not,  on  that  account,  be  able,  while  passing  through  the 
upper  portion  of  the  system,  to  keep  the  temperature  of  the  air 
space  low  enough;  hence  provision  is  made  for  the  reinforcing  of  the 
stream  with  an  additional  quantity  of  cold  water  while  it  is  running 
through  the  upper  part  of  the  bath. 


The  water  is  pumped  first  over  the  cool  surface — i.  e.,  the  pipes 
near  the  bottom,  and  then  over  a  heated  surface  which  consists  of 
two  stoves,  either  of  which  may  be  operated  independently  of  the 
other,  though  both  are  under  the  control  of  the  same  thermostat. 
The  stoves  consist  of  a  high  candle  power  electric  bulb  enclosed  in 
a  galvanized  iron  tube  which  is  located  in  the  end  of  the  bath  not 
covered  by  the  superstructure. 

These  arrangements  are  satisfactory  for  the  maintenance  of  con- 
stant temperatures  in  the  lower  section  of  the  bath — i.  e.,  in  the 
water  in  which  the  osmotic  cells  are  placed  for  a  measurement  of 
pressure,  but  they  were  found  to  be  insufficient  to  maintain  the  same 
temperatures  in  the  upper  section — i.  e.,  in  the  air  space  in  which 
the  upper  ends  of  the  manometers  are  located.  Even  the  rapid  pump- 
ing of  the  air  in  this  section  through  the  pipes  lying  in  the  water, 
and  the  introduction  of  a  small  fan,  propelled  from  the  outside,  to 
agitate  the  air,  did  not  fully  neutralize  the  effect  of  external  condi- 
tions. It  was  therefore  decided  to  bring  these  external  conditions 
under  better  control  by  making  the  necessary  provision  for  keeping, 
outside  of  the  bath,  approximately  the  same  temperature  as  was 
maintained  on  the  inside. 

The  bath  is  located  in  a  room,  3.3  meters  in  length,  2  meters 
in  width,  and  2.6  meters  in  height.  This  space  is  now  regulated  by 
heating  and  cooling  devices  as  occasion  demands.  The  cooling  de- 
vice consists  of  a  series  of  galvanized  iron  pipes,  having  a  total  length 
of  100  meters,  through  which  the  hydrant  water  circulates.  Half  of 
the  pipe  is  suspended  from  the  top  of  the  room  in  parallel  lengths 
equal  to  the  length  of  the  room.  These  pipes  have  a  diameter  of 
about  50  mm.  and  present,  therefore,  a  large  cooling  surface.  The 
remainder  of  the  pipe  is  smaller  (25  mm.  in  diameter),  and  is  cut 
into  two-meter  lengths,  which  are  compactly  ai  ranged  in  a  large 
ice  box.  The  water  enters  the  ice  box  directly  from  the  main  supply, 
and,  after  passing  through  the  series  of  pipes  in  the  box,  ascends 
through  a  vertical  pipe  to  the  system  of  symmetrically  distributed 
large  ones  in  the  top  of  the  room. 

There  are  two  varieties  of  heating  devices  in  use.  One  of  these 
consists  of  two  small  electric  stoves  (incandescent  lamps  in  galvan- 
ized iron  cylinders),  which  are  situated  outside  the  bath,  but  are 
controlled  by  a  thermostat  in  the  air  space  of  the  bath.  The  other 
heating  arrangement  is  a  gas  stove  controlled  by  a  thermostat  situ- 
ated outside  the  bath,  and  set  for  a  temperature  which  is  a  degree 
or  two  below  the  temperature  to  be  maintained  in  the  bath,  so  that 
the  final  heating  of  the  room  may  always  be  accompanied  by  the 
electric  stoves.  The  gas  stove  is,  therefore,  only  used  when  much 
heat  is  needed.  Since  the  electric  stoves  are  regulated  by  the  ther- 
mostat in  the  air  space  of  the  bath  they  can  burn  only  so  much  as 
is  necessary  to  bring  the  temperature  of  the  space  up  to  that  of  the 
water  in  the  bath.  The  air  in  the  room  is  kept  in  constant  circula- 
tion by  a  motor  fan  which  is  located  with  a  view  to  keeping  the 
temperature  of  all  parts  of  the  room  as  uniform  as  possible.  This 
fan  is  operated  by  the  motor  which  runs  the  pumps  in  the  bath. 

Another  device  which  can  be  used  at  times  to  bring  the  tem- 
perature of  the  room  to  the  desired  point,  when  the  temperature  out 
of  doors  is  lower  and  that  of  the  room  higher  than  desired,  or,  when 
that  out  of  doors  is  higher  and  that  of  the  room  lower  than  desired, 
consists  of  a  large  wooden  air  shaft  running  from  a  window,  over 
the  room  in  which  the  bath  is  placed,  and  making  a  right  angle  bend 
opening  'through  the  roof  of  the  bath  room  near,  and  back  of,  the 
fan  above  mentioned.  Air  from  the  outside  is  pumped  into  the  room, 


when  desired,  by  a  motor  fan  placed  in  the  shaft,  taken  up  by  the 
fan  in  the  room,  and  kept  in  circulation. 

With  these  facilities  for  cooling  and  heating,  a  variety  of  con- 
stant temperatures  can  be  kept.  Most  of  the  measurements  of  this 
series  were  taken  without  the  use  of  ice.  We  were,  however,  com- 
pelled to  use.  ice  around  the  block  tin  coil  with  several  measurements 
towards  the  end  of  the  work.  Constant  temperature  of  both  water 
in  the  bath  and  the  air  space  above  the  water  was  maintained  through- 
out the  series,  except  in  two  or  three  instances,  and  these  variations 
were  due  to  accidental  and  temporary  influences,  and  not  to  any 
defect  in  the  temperature  regulation  system.  .  The  variations  from 
5°  were  so  small  in  amount,  and  maintained  for  so  short  a  time, 
that  it  is  not  thought  that  the  ratio  of  osmotic  to  gas  pressure  was 
sensibly  affected. 

A  further  improvement  in  temperature  regulation  as  applied 
to  the  measurement  of  osmotic  pressure  consists  of  a  small  bath 
constructed  much  on  the  same  lines  as  the  large  bath  in  which  the 
measurement  of  osmotic  pressure  proceeds.  This  small  bath  is  placed 
in  the  main  laboratory  room  where  the  work  of  setting  up  the  cell 
is  done.  It  is  kept  at  the  same  temperature  as  the  large  bath  in 
which  the  measurements  are  made.  The  use  of  this  bath  is  to  bring 
the  solution  whose  pressure  is  to  be  measured,  and  the  liquids  in 
which  the  cells  are  immersed  during  the  measurement  to  the  tem- 
perature at  which  the  osmotic  pressure  is  to  be  measured.  This 
bath  is  also  used  to  maintain  the  filled  and  closed  cells  at  the  right 
temperature,  while  they  are  under  observation,  before  going  into  the 
large  bath.  A  full  description  of  these  baths  was  given  by  Morse 
and  Holland  in  The  American  Chemical  Journal  for  February,  1909. 

It  is  probable  that  a  large  part  of  the  variation  in  osmotic  pres- 
sure, which  is  still  found  in  some  duplicate  measurements,  is  due  to 
inaccuracies  in  the  manometers.  During  the  present  year  much  time 
has  been  spent  in  calibrating  and  re-checking  the  nitrogen  volumes 
of  the  manometers  in  use.  The  general  method  employed  in  this 
part  of  the  work  has  been  described  by  Morse  and  Lovelace  in  the 
American  Chemical  Journal  for  October,  1908.  All  the  manometers 
used  in  this  series  of  measurements  had  their  nitrogen  volumes  re- 
determined  just  prior  to  the  commencement  of  the  work.  A  new 
cathetometer  has  recently  been  installed  and  a  small  house  especially 
built  for  the  apparatus  used  in  the  calibration  of  manometers  and  in 
the  comparison  of  them  with  the  standard  manometer.  The  temper- 
ature inside  this  house  is  regulated  by  an  electric  stove  and  fan  to 
keep  the  air  in  circulation,  so  that  the  work  of  comparison  of  manom- 
eters and  the  determination  of  their  nitrogen  volumes  may  proceed 
at  a  constant  temperature,  and,  therefore,  more  rapidly  as  well  as 
more  accurately. 

That  the  improvements  outlined  above  have  resulted  in  increased 
accuracy  in  the  work  is  evident  from  a  comparison  of  the  osmotic 
pressures  now  obtained  with  those  obtained  in  earlier  series.  It  will 
be  noticed  that  the  actual  osmotic  pressures  now  measured  are  some- 
what greater  than  those  obtained  in  former  series.  Eight  series  of 
measurements  at  temperatures  from  0°  to  25°  have  been  carried  out 
before  this  one.  In  the  earlier  ones  the  evidence  bearing  upon  the 
temperature  coefficient  of  osmotic  pressure  was  of  a  very  unsatis- 
factory kind.  In  the  later  work,  in  which  a  greater  degree  of  accu- 
racy had  been  secured,  the  evidence  of  the  existence  of  a  temperature 
coefficient  became  clear,  but  its  exact  amount  was  not  determined 
because  the  conditions  surrounding  the  several  series  were  somewhat 
different,  the  recent  improvements  in  method  were  not  in  use  with 

8 


all  of  them.  In  all  of  the  series  up  to  the  eighth  there  was  more  or 
less  dilution  of  the  cell  contents,  which  certainly  accounts  for  a  part 
of  the  difference  between  the  pressure  observed  then  and  that  found 
in  this  series  and  others  that  have  been  carried  out  under  the  new 
conditions.  If  the  temperature  coefficient  of  osmotic  pressure  is  to 
be  measured,  it  is  essential  that  the  conditions  surrounding  the 
measurements  in  the  several  series  be  as  near  uniform  as  possible. 

During  the  measurements  taken  at  20°  during  the  early  part  of 
the  year,  the  supply  of  sugar,  which  had  been  used  for  the  series, 
became  exhausted.  A  new  supply  of  the  purest  rock  candy  obtain- 
able was  secured,  but  it  showed  evidence  of  the  presence  in  it  of 
considerable  quantities  of  a  reducing  sugar.  It  was,  therefore,  found 
necessary  to  purify  the  sugar  to  be  used.  This  purification  has  been 
carried  on  by  Mr.  W.  M.  Clark  on  a  large  scale.  As  much  as  150 
pounds  of  rock  candy  has  been  used.  The  method  of  purification  is 
in  brief  as  follows:  The  sugar  is  dissolved  in  a  small  amount  of 
water  at  60°  and  precipitated  with  97%  alcohol.  At  first  this  process 
was  repeated  three  times.  However,  analyses  of  the  material  from 
the  second  and  third  crystallizations,  as  well  as  polariscope  deter- 
minations and  the  measurement  of  the  osmotic  pressure,  showed  no 
difference  in  the  two  samples,  so  the  last  precipitation  was  omitted. 
The  precipitate  was  washed  with  ethyl  alcohol  and  finally  with  methyl 
alcohol.  After  being  air  dried  at  ordinary  temperatures,  the  sugar 
was  placed  in  a  60°  air  bath  for  several  days,  and  finally  dried  over 
calcium  chloride  in  a  dessicator. 

It  is  intended  that  enough  sugar  be  prepared  in  this  way  to 
suffice  for  all  future  measurements  with  cane  sugar.  All  the  measure- 
ments at  5°  were  taken  with  sugar  purified  as  above  explained. 

The  tables  which  follow  record  the  results  of  the  work  at  5° 
under  the  new  conditions.  These  results  will  be  compared  with  the 
results  obtained  in  the  series  at  other  temperatures.  The  series  at 
0°  and  10°  have  already  been  completed.  Those  at  15°,  20°,  25°  and 
30°  will  be  carried  out  as  soon  as  possible.  Tables  I-XXIII  show 
the  results  of  the  individual  measurements  in  some  detail.  Table 
XXIV  gives  the  summarized  results  for  each  experiment,  and  in 
Table  XXV  the  mean  values  for  each  concentration  are  shown. 
Tables  XXVI  and  XXVII  are  introduced  for  the  purpose  of  com- 
paring the  results  obtained  at  5°  with  those  obtained  at  0°  and  10° 
in  respect  to  the  osmotic  pressures  and  the  ratio  of  osmotic  to  gas 
pressure. 

TABLE   I. 

0.1  Wt.  normal  solution.  Exp.  No.  1.  Rotation:  (1)  original,  12°.G5;  (2) 
at  conclusion  of  expr.,  12°.65;  loss,  0.0.  Manometer:  No.  13;  volume  of  nitro- 
gen, 263.04;  displacement,  0.0  M.M.  Cell  used,  K3.  Resistance  of  membrane, 
366,000.  Corrections:  (1)  atmospheric  pressure,  0.991;  (2)  liquids  in  manome- 
ter, 0.489;  (3)  dilution,  0;  (4)  concentration,  0;  (5)  capillary  depression,  0.02. 
Initial  pressure,  2.30.  Time  of  setting  up  cell,  3:00  p.  m.,  Feb.  22,  1909. 

Temperature  Volume  Pressure 

Time  Solution  Manometer  N2  Osmotic         Gas        Difference 
Feb.  23. 

12 :30  p.  m.  5°.0  5°.0  89.21  2.455             2.267             0.188 

4 :30  p.  m.  5°.0  5°.0  89.34  2.455             2.267             0.188 
Feb.  24. 

9 :00  a.  m.  5°.0  5°.0  89.95  2.450             2.267             0.183 

1:00  p.m.  5°.0  5°.0  90.12  2.447             2.267             0.180 

2.452  2.267  0.185 

Molecular  osmotic  pressure.  24.520. 
Molecular  gas  pressure,  22.674. 
Ratio  of  osmotic  to  gas  pressure,  1.082. 


TABLE  II. 

0.1  Wt.  normal  solution.  Exp.  No.  2.  Rotation:  (1)  original,  12°.65;  (2) 
at  conclusion  of  expr.,  12°. 65;  loss,  0.0.  Manometer:  No.  6;  volume  of  nitro- 
gen, 412.00;  displacement,  0.0  M.M.  Cell  used,  L3.  Resistance  of  membrane, 
550,000.  Corrections:  (1)  atmospheric  pressure,  0.999;  (2)  liquids  in  manome- 
ter, 0.419;  (3)  dilution,  0;  (4)  concentration,  0;  (5)  capillary  depression,  0.02. 
Initial  pressure,  2.39.  Time  of  setting  up  cell,  3:00  p.  m.,  Feb.  22,  1909. 


Time 

Feb.  23. 
9:00  a.  m. 
5  :30  p.  m. 

Feb.  24. 

10 :00  a.  m. 

2 :00  p.  m. 


Temperature 

Solution    Manometer 


5°.0 
5°.0 


5°.0 
5°.0 


5°.0 
5°.0 


5°.0 
5°.0 


Volume 

N2 

136.66 
136.59 

136.77 
136.90 


Molecular  osmotic  pressure,  24.520. 

Molecular  gas  pressure,  22.674. 

Ratio  of  osmotic  to  gas  pressure,  1.082. 


Pressure 

Osmotic         Gas       Difference 


2.457 
2.453 


2.447 
2.450 


2.452 


2.267 
2.267 


2.267 
2.267 


2.267 


0.190 
0.186 


0.180 
0.183 


0.185 


TABLE  III. 

0.1  Wt.  normal  solution.  Exp.  No.  3.  Rotation:  (1)  original,  12°.6;  (2) 
at  conclusion  of  expr.,  12°. 6;  loss,  0.0.  Manometer:  No.  13;  volume  of  nitro- 
gen, 263.04;  displacement,  0.0  M.M.  Cell  used,  J3.  Resistance  of  membrane, 
228,000.  Corrections:  (1)  atmospheric  pressure,  0.995;  (2)  liquids  in  manome- 
ter, 0.488;  (3)  dilution,  0;  (4)  concentration,  0;  (5)  capillary  depression,  0.02. 
Initial  pressure,  2.36.  Time  of  setting  up  cell,  3:00  p.  m.,  Feb.  25,  1909. 


Time 
Feb.  26. 
10 :00  a.  m. 
4:30  p.  m. 
Feb.  27. 
1 :00  a.  m. 
9  :€0  a.  m. 


Temperature 

Solution    Manometer 


5°.0 
5°.0 

5°.0 
5°.0 


5°.0 
5°,0 

5°.0 
5°.0 


Volume 

N2 


89.27 
89.44 


Molecular  osmotic  pressure,  24.530. 

Molecular  gas  pressure,  22.674. 

Ratio  of  osmotic  to  gas  pressure,  1.082. 


Pressure 

Osmotic         Gas       Difference 


2.453 
2.454 

2.456 
2.448 

2.453 


2.267 
2.267 

2.267 
2.267 

2.267 


0.186 
0.187 

0.189 
0.181 

0.186 


TABLE  IV. 

0.2  Wt.  normal  solution.  Exp.  No.  1.  Rotation:  (1)  original,  24°.9;  (2) 
at  conclusion  of  expr.,  24°.9;  loss,  0.0.  Manometer:  No.  6;  volume  of  nitrogen, 
412.00;  displacement.  0.0  M.M.  Cell  used,  F3.  Resistance  of  membrane,  565.- 
000.  Corrections:  (1)  atmospheric  pressure,  0.989;  (2)  liquids  in  manometer, 
0.515;  (3)  dilution,  0;  (4)  concentration,  0;  (5)  capillary  depression,  0.02. 
Initial  pressure,  4.55.  lime  of  setting  up  cell,  3:00  p.  m.,  Jan.  25,  1909. 


Time 

Jan.  27. 

9 :00  a.  m. 

11 :00  p.  m. 

Jan.  28. 
9:00  a.  m. 
3:30  p.  m. 


Temperature 

Solution    Manometer 


5°.0 
5°.0 


5°.0 
5°.0 


5°.0 
5°.0 


5°.0 
5°.0 


Volume 

N, 


77.90 
77.98 


77.90 
77.97 


Molecular  osmotic  pressure,  24.060. 

Molecular  gas  pressure,  22.674. 

Ratio  of  osmotic  to  gas  pressure,  1.061. 

10 


Pressure 

Osmotic         Gas       Difference 


4.813 
4.816 


4.812 
4.807 


4.812 


4.535  0.278 

4.535  0.281 


4.535 
4.535 


4.535 


0.277 
0.272 


0.277 


TABLE   V. 

0.2  Wt.  normal  solution.  Exp.  No.  2.  Rotation:  (1)  original,  24°. 95;  (2) 
at  conclusion  of  expr.,  24°.95;  loss,  0.0.  Manometer:  No.  9;  volume  of  nitro- 
gen, 454.14;  displacement,  0.0  M.M.  Cell  used,  J3.  Resistance  of  membrance, 
270,000.  Corrections:  (1)  atmospheric  pressure,  0.996;  (2)  liquids  in  manome- 
ter, 0.507;  (3)  dilution,  0;  (4)  concentration,  0;  (5)  capillary  depression,  0.02. 
Initial  pressure,  4.70.  Time  of  setting  up  cell,  12:00  in.,  Feb.  17,  1909. 


Time 

Feb.  18. 

9:00  a.  m. 
12 :30  p.  m. 

Feb.  19. 
12 :30  p.  m. 

4:00  p.  m. 


Temperature 

Solution    Manometer 


5°.0 
5°.0 


5°.0 
5°.0 


5°.0 
5°.0 

5°.0 
5°.0 


Volume 

N2 


85.52 
85.51 


86.03 


Molecular   osmotic   pressure,   24.130. 

Molecular  gas  pressure,  22.674. 

Ratio  of  osmotic  to  gas  pressure,  1.064. 


Pressure 

Osmotic         Gas       Difference 


4.830 
4.833 


4.820 
4.823 


4.826 


4.535 
4.535 


4.535 
4.535 


4.535 


0.295 
0.298 


0.285 
0.288 


0.291 


TABLE  VI. 

0.3  Wt.  normal  solution.  Exp.  No.  1.  Rotation:  (1)  original,  36°.6;  (2) 
at  conclusion  of  expr.,  36°.6;  loss,  0.  Manometer:  No.  6;  volume  of  nitro- 
gen, 412.00;  displacement,  0.0  M.M.  Cell  used,  Jn.  Resistance  of  membrane, 
366,500.  Corrections:  (1)  atmospheric  pressure,  0.997;  (2)  liquids  in  manome- 
ter, 0.527;  (3)  dilution,  0;  (4)  concentration,  0;  (5)  capillary  depression,  0.02. 
Initial  pressure,  5.66.  Time  of  setting  up  cell,  3:30  p.  m.,  Jan.  28,  1909. 


Time 
Jan.  29. 
9:00  a.  m. 
5:00  p.  m. 
Jan.   30. 
10 :00  a.  m. 
1 :00  p.  m. 


Temperature 

Solution    Manometer 


5°.0 

5°.0 


5°.0 
5°.0 


5°.0 
5°.0 


5°.0 
5°.0 


Volume 

N2 

53.88 
54.10 

54.11 
54.12 


Molecular  osmotic  pressure,  23.977. 

Molecular  gas  pressure,  22.674. 

Ratio  of  osmotic  to  gas  pressure,  1.058. 


Pressure 

Osmotic         Gas       Difference 


7.208 
7.190 


7.187 

7.185 


M93 


6.802 
6.802 

6.802 
6.802 

6.802 


0.406 

0.3S8 


0.385 
0.383 


0.391 


TABLE  VII. 

0.3  Wt.  normal  solution.  Exp.  No.  2.  Rotation:  (1)  original,  36°.6;  (2) 
at  conclusion  of  expr.,  36°. 6;  loss,  0.0.  Manometer:  No.  9;  volume  of  nitro- 
gen, 454.14;  displacement,  0.0  M.M.  Cell  used,  K3.  Resistance  of  membrane, 
224,000.  Corrections:  (1)  atmospheric  pressure,  0.994;  (2)  liquids  in  manome- 
ter, 0.544;  (3)  dilution,  0;  (4)  concentration,  0;  (5)  capillary  depression,  0.02. 
Initial  pressure,  6.89.  Time  of  setting  up  cell,  12  :30  p.  m.,  Feb.  13,  1909. 


Time 

Feb.  15. 

12 :00      in. 

5:00  p.  m. 

11:00  p.m. 

Feb.  16. 
12 :00      m. 


Temperature 

Solution    Manometer 


5.°0 
5°.0 
5°.0 

5°.0 


5°.0 
5°.0 
5°.0 

5°.0 


Volume 

N2 

59.34 
59.41 
59.45 

59.54 


Pressure 

Osmotic         Gas  Difference 

7.219  6.802  0.417 

7.212  6.802  0.410 

7.209  6.802  0.407 


Molecular  osmotic  pressure,   24.030. 

Molecular  gas  pressure,  22.674. 

Ratio   of  osmotic  to   gas   pressure,   1.060. 

11 


7.195 
7.209 


6.802 
6.S02 


0.393 
0.407 


TABLE  VIII. 

0.4  Wt.  normal  solution.  Exp.  No.  1.  Rotation:  (1)  original,  47°.95;  (2) 
at  conclusion  of  expr.,  47°.95;  loss,  0.0.  Manometer:  No.  13;  volume  of  nitro- 
gen, 263.04;  displacement,  0.0  M.M.  Cell  used,  F3.  Resistance  of  membrane, 
550,000.  Corrections:  (1)  atmospheric  pressure,  1.025;  (2)  liquids  in  manome- 
ter, 0.572;  (3)  dilution,  0;  (4)  concentration,  0;  (5)  capillary  depression,  0.02. 
Initial  pressure,  7.27.  Time  of  setting  up  cell,  12:00  m.,  Jan.  30,  1909. 

Pressure 

Osmotic         Gas       Difference 

9.622  9.070  0.552 

9.622  9.070  0.552 

9.623  9.070  0.553 


Time 

Feb.  1. 
9:30  a.  m. 
1  :00  p.  m. 
10:00  p.  m. 
Feb.  2. 
9:00  a.  m. 

Temperature 

Solution    Manometer 

5°.0            4°.9o 
5°.0            5°.0 
5°.0             5°.0 

5°.0             5°.0 

Volume 

N2 

26.20 
26.19 
26.18 

26.19 

Molecular  osmotic  pressure,  24.058. 

Molecular  gas  pressure,  22.674. 

Ratio  of  osmotic  to  gas  pressure,  1.061. 


9.625 
9.623 


9.070 
9.070 


0.555 
0.553 


TABLE  IX. 

0.4  Wt.  normal  solution.  Exp.  No.  2.  Rotation:  (1)  original,  47°.9o;  (2) 
at  conclusion  of  expr.,  47°.95;  loss,  0.0.  Manometer:  No.  9;  volume  of  nitro- 
gen, 454.14;  displacement,  0.0  M.M.  Cell  used,  K3.  Resistance  of  membrane, 
550,000.  Corrections:  (1)  atmospheric  pressure,  0.996;  (2)  liquids  in  manome- 
ter, 0.561;  (3)  dilution,  0;  (4)  concentration,  0;  (5)  capillary  depression,  0.02. 
Initial  pressure,  9.28.  Time  of  setting  up  cell,  12:00  m.,  Jan.  30,  1909. 


Temperature 

Volume 

Time 

Solution 

Manometer 

N2 

Jan.  30. 

10  :30  p.  m. 

5°.0 

5°.0 

45.21 

Jan.  31. 

11:30  a.  m. 

5°.0 

4°.  95 

45.21 

5:30  p.  m. 

5°.0 

4°.95 

45.25 

Feb.  1. 

4:00  p.  m. 

5°.0 

5°.0 

45.38 

Molecular  osmotic  pressure,  24.043. 

Molecular  gas  pressure,  22.674. 

Ratio   of  osmotic  to   gas  pressure,   1.000. 


Osmotic 

Pressure 

Gas 

Difference 

9.644 

9.070 

0.574 

9.631 
9.623 

9.070 
9.070 

0.561 
0.553 

9.571 
9.617 

9.070 
9.070 

0.501 

0.547 

TABLE  X. 

0.5  Wt.  normal  solution.  Exp.  No.  1.  Rotation:  (1)  original,  58°. 7;  (2) 
at  conclusion  of  expr.,  58°.7;  loss,  0.0.  Manometer:  No.  9;  volume  of  nitro- 
gen, 454.14;  displacement,  0.0  M.M.  Cell  used,  H3.  Resistance  of  membrane, 
500,000.  Corrections:  (1)  atmospheric  pressure,  1.005;  (2)  liquids  in  manome- 
ter, 0.573;  (3)  dilution,  0;  (4)  concentration,  0;  (5)  capillary  depression.  0.02. 
Initial  pressure,  13.00.  Time  of  setting  up  cell,  3:00  p.  m.,  Jan.  21,  1909. 


Time 

Jan.  22. 
9 :00  a.  m. 
1 :00  p.  m. 
5:00  p.  m. 

Jan.  23. 
2:30  p.  m. 


Temperature 

Solution    Manometer 


5°.0 
5°.0 
5°.0 

5°,0 


5°.0 
5°.0 


5°.0 


Volume 

N2 

36.22 
86.26 


Pressure 

Osmotic         Gas       Difference 


12.122  11.337 

12.100  11,337 

12.097  11.337 


Molecular  osmotic  pressure,  24.176. 

Molecular  gas  pressure,  22.674. 

Ratio  of  osmotic  to  gas   pressure,  1.066. 

12 


12.028 
12.089 


11.337 
11.337 


0.785 
0.772 
0.760 

0.691 
0.752 


TABLE  XI. 

0.5  Wt.  normal  solution.  Exp.  No.  2.  Rotation:  (1)  original  58°. 7;  (2) 
at  conclusion  of  expr.,  58°. 7;  loss,  0.0.  Manometer:  No.  13;  volume  of  nitro- 
gen, 263.04;  displacement,  0.0  M.M.  Cell  used,  E3.  Resistance  of  membrane, 
550,000.  Corrections:  (1)  atmospheric  pressure,  0.999;  (2)  liquids  in  manome- 
ter, 0.580;  (3)  dilution,  0;  (4)  concentration,  0;  (5)  capillary  depression,  0.02. 
Initial  pressure,  10.74.  Time  of  setting  up  cell,  3:30  p.  m.,  Jan.  22,  1909. 


Temperature 


Volume 
N, 

21.04 
21.04 

21.06 

21.07 


Molecular  osmotic  pressure,  24.186. 

Molecular  gas  pressure,  22.674. 

Ratio  of  osmotic  to  gas  pressure,  1.067. 


Time 

Solution    1 

lauome 

Jan.  23. 

3:00  a.  m. 

5°.0 

5°.2 

2  :30  p.  m. 

5°.0 

5°.0 

Jan.  24. 

5:00  p.  m. 

5°.0 

5°.2 

Jan.   25. 

9:00  a.  m. 

5°.0 

5°.  05 

Pressure 

Osmotic         Gas       Difference 


12.088 
12.100 

12.097 
12.087 
12.093 


11.337 
11.337 

11.337 
11.337 
11.337 


0.751 
0.763 

0.760 
0.750 
0.756 


TABLE  XII. 

0.6  Wt.  normal  solution.  Exp.  No.  1.  Rotation:  (1)  original,  69°.2;  (2) 
at  conclusion  of  expr.,  69°.2;  loss,  0.0.  Manometer:  No.  20;  volume  of  nitro- 
gen, 411.07;  displacement,  0.0  M.M.  Cell  used,  L3.  Resistance  of  membrane, 
370,000.  Corrections:  (1)  atmospheric  pressure,  1.001;  (3)  liquids  in  manome- 
ter, 0.578;  (3)  dilution,  0;  (4)  concentration,  0;  (5)  capillary  depression,  0.02. 
Initial  pressure,  13.59.  Time  of  setting  up  cell,  4:00  p.  m.,  Feb.  1,  1909. 


Time 

Feb.  2. 

9:00  a.  m. 

4:30  p.  m. 

Feb.   3. 

9:00  a.  m. 

12  :30  p.  m. 


Temperature 

Solution    Manometer 


5°.0 
5°.0 


5°.0 
5°.0 


5°.0 
5°.0 


5°.0 
5°.0 


Volume 

N2 

Osmotic 

Pressure 
Gas 

Difference 

27.38 
27.40 

14.611 
14.601 

13.604 
13.604 

1.007 
0.997 

27.41 
27.40 

14.599 
14.608 
14.605 

13.604 
13.604 
13.604 

0.995 
1.004 
1.001 

Molecular  osmotic  pressure,  24.342. 

Molecular  gas  pressure,  22.674. 

Ratio  of  osmotic  to  gas  pressure,  1.074. 


TABLE    XIII. 

0.6  Wt.  normal  solution.  Exp.  No.  2.  Rotation:  (1)  original,  69°.2;  (2) 
at  conclusion  of  expr.,  69°.2;  loss,  0.0.  Manometer:  No.  11;  volume  of  nitro- 
gen, 431.37;  displacement,  0.0  M.M.  Cell  used,  I3.  Resistance  of  membrane,  367,- 
000.  Corrections:  (1)  atmospheric  pressure,  1.001;  (2)  liquids  in  manometer, 
0.561;  (3)  dilution,  0;  (4)  concentration,  0;  (5)  capillary  depression,  0.02. 
Initial  pressure,  10.28.  Time  of  setting  up  cell,  4:00  p.  m.,  Feb.  1,  1909. 


Time 

Feb.  2. 

9:00  a.  m. 

1:00  p.  m. 

Feb.   3. 

9:00  a.  m. 

12  :30  p.  m. 


Temperature 

Solution    Manometer 


5°.0 
5°.0 


5°.0 
5°.0 


5°.0 
5°.0 


5°.0 
5°.0 


Volume 


28.69 

28.68 


28.72 

28.75 


Molecular   osmotic   pressure,   24.340. 

Molecular  gas  pressure,  22.674. 

Ratio  of  osmotic  to  gas  pressure,  1.074. 

13 


Osmotic 


14.604 
14.617 


14.602 
14.591 


14.604 


Pressure 

Gas       Difference 


13.604 
13.604 


13.601 
13.604 


13.604 


1.000 
1.013 


0.998 
0.9S7 


1.000 


TABLE  XIV. 

0.7  Wt.  normal  solution.  Exp.  No.  1.  Rotation:  (1)  original,  79°.3;  (2) 
at  conclusion  of  expr.,  79°.3;  loss,  0.0.  Manometer:  No.  9;  volume  of  nitro- 
gen, 454.14;  displacement,  0.0  M.M.  Cell  used,  M3.  Resistance  of  membrane, 
275,000.  Corrections:  (1)  atmospheric  pressure,  0.994;  (2)  liquids  in  manome- 
ter, 0.585;  (3)  dilution,  0;  (4)  concentration,  0;  (5)  capillary  depression,  0.02. 
Initial  pressure,  15.51.  lime  of  setting  up  cell,  3:30  p.  in.,  Feb.  2,  1909. 


Time 

Feb.   3. 
12  :30  p.  m. 
10:00  p.  m. 
Feb.  4. 
9  :30  a.  m. 
3:00  p.  m. 

Temperature 

Solution    Manometer 

5°.0            5°.0 
5°.0            5°.0 

5°.0            5°.05 
5°.0             5°.0 

Volume 

N2 

25.77 
25.79 

25.80 
25.83 

Osmotic 

17.235 
17.220 

17.215 
17.199 

Pressure 

Gas 

15.872 
15.872 

15.872 
15.872 

Difference 

1.363 
1.348 

1.343 
1.327 

Molecular  osmotic  pressure,  24.596. 

Molecular  gas  pressure,  22.674. 

Ratio  of  osmotic  to  gas  pressure,  1.085. 


17.217 


15.872 


1.345 


TABLE  XV. 

0.7  Wt.  normal  solution.  Exp.  No.  2.  Rotation:  (1)  original,  79°.2;  (2) 
at  conclusion  of  expr.,  79°.2;  loss,  0.0.  Manometer:  No.  6;  volume  of  nitro- 
gen, 412.00;  displacement,  0.0  M.M.  Cell  used,  J3.  Resistance  of  membrane, 
270.000.  Corrections:  (1)  atmospheric  pressure,  1.004;  (2)  liquids  in  manome- 
ter, 0.569;  (3)  dilution,  0;  (4)  concentration,  0;  (5)  capillary  depression,  0.02. 
Initial  pressure,  15.11.  Time  of  setting  up  cell,  12:30  p.  in.,  Feb.  11,  1909. 


Time 

Feb.  12. 
1:00  p.  m. 
5:00  p.  m. 
Feb.  13. 
10 :30  a.  m. 
3:00  p.  m. 


Temperature 

Solution    Manometer 


5°.0 
5°.0 


5°.0 
5°.0 


5°.0 

5°.0 


5°.0 


Volume 

N2 

Osmotic 

Pressure 

Gas 

Difference 

23.39 
23.41 

17.196 
17.185 

15.872 
15.872 

1.324 
1.313 

23.40 
23.39 

17.192 
17.204 

15.872 
15.872 

1.320 
1.332 

Molecular   osmotic,  pressure.   24.563. 

Molecular  gas  pressure,  22.674. 

Ratio  of  osmotic  to  gas  pressure,  1.083. 


17.194 


15.872 


1.322 


TABLE  XVI. 

0.8  Wt.  normal  solution.  Exp.  No.  1.  Rotation:  (1)  original,  89°.0;  (2) 
at  conclusion  of  expr.,  89°. 0;  loss,  0.0.  Manometer:  No.  20;  volume  of  nitro- 
gent,  411.07;  displacement,  0.0  M.M.  Cell  used,  Jg.  Resistance  of  membrane, 
275,000.  Corrections:  (1)  atmospheric  pressure,  0.986;  (2)  liquids  in  manome- 
ter, 0.586;  (3)  dilution,  0;  (4)  concentration,  0;  (5)  capillary  depression,  0.02. 
Initial  pressure,  19.50.  Time  of  setting  up  cell,  12:30  p.  m.,  Feb.  4,  1909. 


Temperature 


Time 

Solution    Ji 

lanome 

Feb.  4. 

10  :00  p.  m. 

5°.0 

4°.95 

Feb.  5. 

1:00  p.  m. 

5°.0 

5°.0 

9  :30  p.  m. 

5°.0 

5°.4 

Feb.  6. 

12:00      m. 

5°.0 

5°.0 

Volume 

N2 


20.37 


Molecular  osmotic  pressure  ,24.744. 

Molecular  gas  pressure,  22.674. 

Ratio  of  osmotic  to  gas  pressure,  1.091. 

14 


Pressure 

Osmotic         Gas       Difference 


19.79-J 


18.139 


1.6.18 


20.38 
20.33 

19.788 
19.802 

18.139 
18.139 

1.G49 
1.663 

20.38 

19.793 

18.139 

1.654 

19.795 

18.139 

1.656 

TABLE  XVII. 

0.8  Wt.  normal  solution.  Exp.  No.  2.  Rotation:  (1)  original,  89°.0;  J2) 
at  conclusion  of  expr.,  89°.0;  loss,  0.0.  Manometer:  No.  9;  volume  of  nitro- 
gen, 454.14;  displacement,  0.0  M.M.  Cell  used,  B3.  Resistance  of  membrane, 
550,000.  Corrections:  (1)  atmospheric  pressure,  0.985;  (2)  liquids  in  manome- 
ter, 0.591;  (3)  dilution,  0;  (4)  concentration,  0;  (5)  capillary  depression,  0.02. 
Initial  pressure,  16.61.  Time  of  setting  up  cell,  3:00  p.  m./Feb.  9,  1909. 


Time 

Feb.  10. 

9  :00  a.  m. 

5 :00  p.  m. 

10:30  p.  m. 

Feb.  11. 
2:30  p.  m. 


Temperature 

Solution    Manometer 


5°.0 
5°.0 
5°.0 

5°.0 


5°.05 

5°.0 

5°.0 

5°.05 


Volume 

N2 

22.49 
22.46 
22.45 

22.44 


Molecular   osmotic   pressure,   24.806. 

Molecular  gas  pressure,  22.674. 

Ratio  of  osmotic  to  gas   pressure,  1.094. 


Pressure 

Osmotic         Gas  Difference 

19.826  18.139  1.687 

19.850  18.139  1.711 

19.853  18.139  1.714 


19.853 
19.845 


18.139 
18.139 


1.714 
1.706 


TABLE   XVIII. 

0.9  Wt.  normal  solution.  Exp.  No.  1.  Rotation:  (1)  original,  98°.35;  (2) 
at  conclusion  of  expr.,  98°. 35;  loss,  0.0.  Manometer:  No.  20;  volume  of  nitro- 
gen, 411.13;  displacement,  0.0  M.M.  Cell  used,  O3.  Resistance  of  membrane, 
550,000.  Corrections:  (1)  atmospheric  pressure,  1,005;  (2)  liquids  in  manome- 
ter, 0.590;  (3)  dilution,  0;  (4)  concentration,  0;  (5)  capillary  depression,  0.02. 
Initial  pressure,  22.06.  Time  of  setting  up  cell,  3:00  p.  m.,  Feb.  19,  1909. 


Time 

Feb.  22. 

9 :00  a.  m. 

2:30  p.  m. 

10  :00  p.  m. 

Feb.  23. 
9:00  a.  m. 


Temperature 

Solution    Manometer 


5°.0 
5°.0 
5°.0 

5°.0 


5°.0 
5°.0 
5°.0 

5°.0 


Volume 

N2 

18.00 
18.00 
18.00 

18.01 


Molecular  osmotic  pressure,  24.937. 

Molecular  gas  pressure,  22.674. 

Ratio  of  osmotic  to  gas  pressure,  1.100. 


Pressure 

Osmotic         Gas       Difference 

22.448  20.406  2.042 

22.447  20.406  2.041 

22.445  20.406  2.039 


22.433 
22.443 


20.406 
20.406 


2.027 
2.037 


TABLE    XIX. 

0.9  Wt.  normal  solution.  Exp.  No.  2.  Rotation:  (1)  original,  98°.25;  (2) 
at  conclusion  of  expr.,  98°.25;  loss,  0.0.  Manometer:  No.  9;  volume  of  nitro- 
gen, 454.14;  displacement,  0.0  M.M.  Cell  used,  B3.  Resistance  of  membrane, 
500,000.  Corrections:  (1)  atmospheric  pressure,  1.008;  (2)  liquids  in  manome- 
ter, 0.584;  (3)  dilution,  0;  (4)  concentration,  0;  (5)  capillary  depression,  0.02. 
Initial  pressure,  17.11.  Time  of  setting  up  cell,  3.00  p.  m.,  Jan.  18,  1909. 


Time 

Jan.  19. 
5 :00  p.  m. 

Jan.  20. 
10:00  a.  m. 

Jan.  21. 
1 :00  a.  m. 
9:00  a.  m. 


Temperature 

Solution    Manometer 


5°.0 
5°.0 

5°.0 
5°.0 


5°.0 
5°.0 


4°.8 
5°.0 


Volume 

N2 

19.93 
19.87 

19.80 
19.80 


Molecular   osmotic   pressure,   24.983. 

Molecular  gas  pressure,  22.674. 

Ratio  of  osmotic  to   gas  pressure,  1.102. 

15 


Pressure 

Osmotic         Gas       Difference 


22.391 
22.463 


22.542 
22.545 


22.485 


20.406 
20.406 

20.406 
20.406 

20.406 


1.985 
2.057 

2.136 
2.139 

2.079 


TABLE  XX. 

1.0  Wt.  normal  solution.  Exp.  No.  1.  Rotation:  (1)  original,  107°.3;  (2) 
at  conclusion  of  expr.,  107°.3;  loss,  0.0.  Manometer:  No.  20;  volume  of  nitro- 
gen. 411.07;  displacement,  0.0  M.M.  Cell  used,  C3.  Resistance  of  membrane, 
550.000.  Corrections:  (1)  atmospheric  pressure,  1.009;  (2)  liquids  in  manome- 
ter, 0.592;  (3)  dilution,  0;  (4)  concentration,  0  ;(5)  capillary  depression,  0.02. 
Initial  pressure,  20.12.  Time  of  setting  up  cell,  12:30  p.  in.,  Jan.  16,  1909. 


Temperature 


Volume 


Pressure 


Time 

Jan.  18. 
5  :00  a.  m. 
1:00  p.  m. 
9  :30  p.  m. 
Jan.   19. 
1:00  p.  m. 

Solution 

5°.0 
5°.0 
5°.0 

5°.0 

Manometer 

4°.  95 
5°.0 
5°.0 

5°.0 

16.00 
16.02 
16.01 

16.00 

Osmotic 

25.305 
25.269 
25.279 

25.301 

Gas        : 

22.674 
22.674 
22.674 

22.674 

DiffereiK 

2.631 
2.595 
2.605 

2.627 

Molecular    osmotic    pressure,   25.289. 

Molecular  gas  pressure,  22.674. 

Ratio  of  osmotic  to  gas  pressure,  1.115. 


25.289 


22.674 


2.615 


TABLE   XXI. 

1.0  Wt.  normal  solution.  Exp.  No.  2.  Rotation:  (1)  original,  107°.3;  (2) 
at  conclusion  of  expr.,  107°.3;  loss,  0.0.  Manometer:  No.  9;  volume  of  nitro- 
gen, 454.14;  displacement,  0.0  M.M.  Cell  used,  K«.  Resistance  of  membrane, 
1,100,000.  Corrections:  (1)  atmospheric  pressure,  1.001;  (2)  liquids  in  manome- 
ter, 0.597;  (3)  dilution,  0;  (4)  concentration,  0;  (5)  capillary  depression,  0.02. 
Initial  pressure,  21.83.  Time  of  setting  up  cell,  12:30  p.  m.,  Jan.  16,  1909. 


Time 

Jan.  16. 
9  :00  a.  m. 
Jan.  17. 
7  :30  a.  m. 
11  :00  a.  m. 
9:00  p.  m. 

Temperature 

Solution    Manometer 

5°.0            5°.0 

5°.10           4°.95 
5°.05           4°.95 
5°.0             5°.0 

Volume 

N2 

17.67 

17.68 
17.68 
17.71 

Osmotic 
25.316 

25.309 
25.309 
25.252 

Pressure 

Gas 

22.674 

22.674 
22.674 
22.674 

Difference 
2.642 

2.  (535 
2.635 

2.578 

Molecular  osmotic  pressure,  25.297. 

Molecular  gas  pressure,  22.674. 

Ratio  of  osmotic  to  gas   pressure,  1.115. 


25.297 


22.674 


2.623 


TABLE  XXII. 

1.0  Wt.  normal  solution.  Exp.  No.  3.  Rotation:  (1)  original,  107°.3;  (2) 
at  conclusion  of  expr.,  107°.3;  loss,  0.0.  Manometer:  No.  21;  volume  of  nitro- 
gen, 400.14;  displacement,  0.0  M.M.  Cell  used,  F3.  Resistance  of  membrane, 
1,000,000.  Corrections:  (1)  atmospheric  pressure,  1.005;  (2)  liquids  in  manome- 
ter, 0.642;  (3)  dilution,  0;  (4)  concentration,  0;  (5)  capillary  depression,  0.02. 
Initial  pressure,  18.56.  Time  of  setting  up  cell,  4:30  p.  m.,  Jan.  13,  1909. 


Time 

Jan.  14. 
1  :00  p.  m. 
5:00  p.  m. 
Jan.  15. 
12  :80  a.  m. 
12  :30  p.  m. 

Temperature 

Solution    Manometer 

5°.0            5°.0 
5°.0            5°.l 

4°.95           5°.05 
5°.0             5°.0 

Volume 

N2 

15.59 
15.59 

15.58 
15.61 

Osmotic 

25.315 
25.325 

25.322 
25.286 

Pressure 

Gas 

22.674 
22.674 

22.674 
22.674 

Difference 

2.641 
2.651 

2.648 
2.612 

Molecular  osmotic  pressure,  25.312. 

Molecular   gas   pressure,   22.674. 

Ratio  of  osmotic  to  gas  pressure,  1.116. 

16 


25.312          22.674 


2.638 


TABLE   XXIII. 

1.0  Wt.  normal  solution.  Exp.  No.  4.  Rotation:  (1)  original,  107°.3;  (2) 
at  conclusion  of  expr.,  107°.3;  loss,  0.0.  Manometer:  No.  21;  volume  of  nitro- 
gen, 400.14;  displacement,  0.0  M.M.  Cell  used,  J3.  Resistance  of  membrane, 
1,100.000.  Corrections:  (1)  atmospheric  pressure,  1.004;  (2)  liquids  in  manome- 
ter, 0.642;  (3)  dilution,  0;  (4)  concentration,  0;  (5)  capillary  depression,  0.02. 
Initial  pressure,  20.15.  Time  of  setting  up  cell,  12:30  p.  m.,  Jan.  16,  1909. 


Time 

Jan.  16. 
9:00  a.  m. 
Jan.  17. 
11:00  a.  m. 
9:00  a.  m. 
Jan.  18. 

Temperature 

Solution    Manometer 

5°.0            5°.0 

5°.05          4°.95 
5°.0             5°.0 

Volume 

N2 

15.64 

15.61 
15.63 

Osmotic 
25.234 

25.304 
25.257 

Pressure 

Gas 

22.674 

22.674 
22.674 

Difference 
2.560 

2.630 
2.583 

9 :30  a.  m. 


5°.0 


5°.0 


15.64 


25.232 


22.674 


Molecular  osmotic  pressure,   25.257. 

Molecular  gas  pressure,  22.674. 

Ratio  of  osmotic  to  gas  pressure,  1.114. 


25.257          22.674 


2.558 
2.583 


TABLE    XXIV— SUMMARY    OF    RESULTS    AT    5C 


Ratio  of 

Weight 

Molecular 

Molecular 

osmotic 

normal 

Osmotic 

Gas 

osmotic 

gas 

to  gas 

concentration 

pressure 

pressure 

Difference 

pressure 

pressure 

pressure 

0.1 

2.452 

2.267 

0.185 

24.520 

22.674 

1.082 

0.1 

2.452 

2.267 

0.185 

24.520 

22.674 

1.082 

0.1 

2.453 

2.267 

0.186 

24.530 

22.674 

1.082 

0.2 

4.812 

4.535 

0.277 

24.060 

22.674 

1.061 

0.2 

4.826 

4.535 

0.291 

24.130 

22.674 

1.064 

0.3 

7.193 

6.802 

0.391 

23.977 

22.674 

1.058 

0.3 

7.209 

6.802 

0.407 

24.030 

22.674 

1.060 

0.4 

9.623 

9.070 

0.553 

.24.058 

22.674 

1.061 

0.4 

9.617 

9.070 

0.547 

24.043 

22.674 

1.060 

0.5 

12.089 

11.337 

0.752 

24.176 

22.674 

1.066 

0.5 

12.093 

11.337 

0.756 

24.186 

22.674 

1.067 

0.6 

14.605 

13.604 

1.001 

24.342 

22.674 

1.074 

0.6 

14.604 

13.604 

1.000 

24.340 

22.674 

1.074 

0.7 

17.217 

15.872 

1.345 

24.596 

22.674 

1.085 

0.7 

17.194 

15.872 

1.322 

24.563 

22.674 

1.083 

0.8 

19.795 

18.139 

1.656 

24.744 

22.674 

1.091 

0.8 

19.845 

18.139 

1.706 

24.806 

22.674 

1.094 

0.9 

22.443 

20.406 

2.037 

24.937 

22.674 

1.100 

0.9 

22.485 

20.406 

2.079 

24.983 

22.674 

1.102 

1.0 

25.289 

22.674 

2.615 

25.289 

22.674 

1.115 

1.0 

25.297 

22.674 

2.623 

25.297 

22.674 

1.115 

1.0 

25.312 

22.674 

2.638 

25.312 

22.674 

1.116 

1.0 

25.257 

22.674 

2.583 

25.257 

22.674 

1.114 

TABLE 

XXV—  SUMMARY 

OF   RESULTS 

AT  5°   MEAN   VALUES. 

Ratio  of 

Weight 

Molecular 

Molecular 

osmotic 

normal 

Osmotic 

Gas 

osmotic 

gas 

to  gas 

concentration 

pressure 

pressure 

Difference 

pressure 

pressure 

pressure 

0.1 

2.452 

2.267 

0.185 

24.523 

22.674 

1.082 

0.2 

4.819 

4.535 

0.284 

24.095 

22.674 

1.063 

0.3 

7.201 

6.802 

0.399 

24.003 

22.674 

1.059 

0.4 

9.620 

9.070 

0.550 

24.050 

22.674 

1.061 

05 

12.091 

11.337 

0.754 

24.181 

22.674 

1.067 

06 

14.605 

13.604 

1.001 

24.341 

22.674 

1.074 

0.7 

17.206 

15.872 

1.334 

24.580 

22.674    ' 

1.084 

0.8 

19.820 

18.139 

1.681 

24.775 

22.674 

1.093 

0.9 

22.464 

20.406 

2.058 

24.960 

22.674 

1.101 

1.0 

25.289 

22.674 

2.615 

25.289 

22.674 

1.115 

17 


TABLE  XXVI.     OSMOTIC   PRESSURES  AT  0°   5°,  and  10C 


Weight  normal 
concentration 

0  1 

0° 

5° 
2  452 

10° 
2497 

0.2 
03 

4.724 

7075 

4.819 
7201 

4.895 

0.4 
0.5 
0.6 
0.7 
0.8 
0.9 
1.0 

0.450 
11.897 
14.380 
16.892 
19.476 
22.118 
24.832 

9.620 
12.091 
14.605 
17.206 
19.820 
22.464 
25.289 

9.790 
12.297 
14.851 
17.501 
20.161 
22.886 
25.697 

1. 

Total  pressure  0.4  to  1.0  N. 

119  045 

121  095 

123  183 

2 

Mean  ratio  of  osmotic  to 
gas  pressure,  0.4  to  1.0 
N.  concentration.. 

1.090 

1.090 

1.089 

TABLE    XXVII— MEAN     RATIO     OF     OSMOTIC     TO     GAS     PRESSURES     AT 

0°,   5°,   AND    10° 


Weight  normal 
concentration 

0.1 

0.2 

0.3 

0.4 

0.5 

0.6 

0.7 

0.8 

0.9 

1.0 


0° 

i'.oei 

1.059 
1.061 
1.069 
1.076 
1.084 
1.094 
1.104 
1.115 


5° 

1.082 
1.063 
1.059 
1.061 
1.067 
1.074 
1.084 
1.093 
1.101 
1.115 


10° 
1.082 
1.061 

i'.oei 

1.066 
1.072 
1.083 
1.092 
1.102 
1.114 


Mean  ratios 
1.082 
1.062 
1.059 
1.061 
1.067 
1.074 
1.084 
1.093 
1.102 
1.115 


With  reference  to  Tables  I-XXIII  it  is  only  necessary  to  call 
attention  to  the  fact  that  the  series  of  measurements  was  carried  out 
without  the  least  trace  of  loss  in  rotation.  The  solution  from  the 
cell  after  each  measurement  gave  the  same  rotation  as  a  part  of 
the  original  solution,  which  was  saved  for  this  purpose.  Table  XXIV 
shows  the  osmotic  pressure,  gas  pressure,  the  difference  between  the 
two,  the  molecular  osmotic  and  gas  pressures,  and  the  ratio  of 
osmotic  to  gas  pressure.  A  glance  at  the  ratios  obtained  in  duplicate 
experiments  will  show  how  good  the  agreement  in  the  work  has 
been,  when  it  is  understood  that  exceptional  difficulties  had  to  be 
overcome. 

In  the  0.1  and  0.6  normal  concentrations  the  difference  in  the 
ratio  is  not  apparent  in  the  third  decimal  place.  In  no  case  is  the 
difference  in  the  ratio  greater  than  three  in  the  third  decimal  place. 
In  two  cases  the  difference  in  the  ratio  amounted  to  three  in  the 
third  decimal  place.  In  the  one  case  the  difference  in  actual  osmotic 
pressure  was  only  0.05  of  an  atmosphere,  in  the  other  still  less.  The 
more  concentrated  the  solution  the  less  is  the  ratio  influenced  by 
a  difference  in  the  actual  pressures  measured.  The  largest  divergence 
in  actual  pressures  occurs  with  the  normal  concentration,  as  would 
be  expected.  Here  the  difference  between  the  highest  and  lowest 
of  four  measurements  is  only  0.055  of  an  atmosphere.  In  other  cases, 
the  difference  is  much  less  and  in  some  there  is  no  difference  at  all. 

Table  XXV  shows  the  mean  values.  Attention  may  be  called  to 
the  somewhat  regular  way  in  which  the  ratios  decrease  from  1.0 
to  0.4  normal  concentration.  A  minimum  is  reached  at  0.3  normal,. 

18 


which,  however,  is  very  little  lower  than  the  ratios  at  0.4  and  0.2 
normal,  which  are  very  nearly  equal.  With  the  0.1  normal  there  is 
a  notable  rise  in  the  ratio. 

Table  XXVI  gives  the  actual  pressures  measured  at  0°,  5°,  and 
10°,  with  the  exception  of  the  0.3  normal  concentration  in  the  case 
of  the  10°  series,  and  the  0.1  normal  concentration  in  the  0°  series. 
The  measurement  of  the  pressure  of  these  concentrations  has  not 
been  finished.  Horizontal  column  numbered  1  in  this  table  gives 
the  total  osmotic  pressure  measured  for  concentrations  0.4  normal 
to  1.0  normal  inclusive.  The  three  lower  concentrations  are  omitted 
from  this  summation  because  of  the  blanks  at  0.3  normal  in  the  10° 
series  and  at  0.1  normal  in  0°  series.  It  will  be  seen  that  the  mean 
ratios  of  osmotic  to  gas  pressure  calculated  from  the  total  pressures 
of  the  three  series  are  strikingly  concordant.  The  meaning  of  this 
is  obviously  that  the  law  of  Gay-Lussac  for  gas  pressure  holds  for 
the  osmotic  pressure  of  cane  sugar  solutions  within  the  temperatures 
and  concentrations  in  question,  since  the  gas  pressures  used  in  cal- 
culating the  ratios  are  determined  from  Gay-Lussac's  law. 

The  average  ratios  for  each  of  the  three  series  are  arranged  in 
parallel  columns  in  Table  XXVII.  The  ratios  for  the  different  con- 
centrations for  each  series  may  here  be  compared  with  the  other 
two.  The  agreement  in  every  case  is  excellent.  A  fourth  column 
shows  the  mean  ratios  for  the  three  series.  In  no  case  is  the  differ- 
ence of  any  ratio  from  the  mean  greater  than  two  in  the  third  deci- 
mal place,  and  in  most  cases  it  is  less.  More  than  half  of  the  indi- 
vidual ratios  agree  exactly  with  the  mean.  When  the  work  at  15°, 
20°,  25°,  and  30°  is  completed  the  results  then  obtained  must  be 
compared  with  those  here  set  forth. 

As  far  as  the  work  has  proceeded  it  can  certainly  be  concluded 
that  there  is  a  temperature  coefficient  for  the  osmotic  pressure  of 
cane  sugar  solutions  between  0.1  and  1.0  weight  normal  concentrations, 
and  that  this  temperature  coefficient  is  substantially  identical  with 
that  for  gases. 


19 


BIOGRAPHY. 

Eugene  Edward  Gill  was  born  September  17,  1875,  at  Boring, 
Maryland.  His  early  education  was  obtained  in  the  Baltimore  County 
public  schools  and  at  Franklin  High  School,  Reisterstown,  Maryland. 
He  entered  Dickinson  College,  Carlisle,  Pennsylvania,  in  the  fall  of 
1893,  and  received  the  degree  of  Ph.  B.  in  1897,  and  that  of  A.  M.  in 
1898.  During  the  year  1897-98  he  was  principal  of  the  Montgomery 
(Pa.)  High  School.  From  1898-1900  he  taught  Mathematics  and  Sci- 
ence in  Morrisville  College,  Morrisville,  Missouri.  From  1900  to 
1903  he  engaged  in  business,  and  from  1903  to  1906  he  was  instructor 
of  Chemistry  and  Physics  in  The  Colorado  State  Preparatory  School, 
Boulder,  Colorado.  In  the  fall  of  1906,  he  entered  The  Johns  Hop- 
kins University  as  a  graduate  student  in  the  chemical  department. 
His  -subordinate  subjects  are  Physical  Chemistry  and  Mineralogy. 
While  here  he  ha,s  served  .one  year  as  laboratory  assistant,  and  one 
year  as  lecture  assistant  to*1  Professor  Renouf. 


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